1. Field of the Invention
The present invention relates to an electrical connection structure, a manufacturing method thereof and a semiconductor integrated circuit device, more particularly to an electrical connection structure using elongated carbon structures such as carbon nanotubes, a manufacturing method thereof and a semiconductor integrated circuit device.
2. Description of the Related Art
In semiconductor integrated circuit devices including semiconductor devices and printed circuit boards, via structures are widely applied in which electroconductive materials are formed in via holes installed in the interlayer insulating films, substrates and the like in order to electrically connect wires and other electrical conductors present in different layers or planes.
Copper (Cu) is often used as a wiring material, and via holes which have been formed at specific positions so as to communicate with such copper wiring are generally filled with an electroconductive metal material such as Cu in order to form vias.
In recent years, research has been done into using so-called carbon nanotubes (CNTs) or cylindrical carbon materials found in carbon fibers for such vias in addition to metal materials such as Cu. In particular, many characteristics of CNTs such as excellent chemical stability and unique physical and electrical properties have made them a focus of interest as materials for forming semiconductor devices, and, besides controlling of their thickness and length, for example, a variety of studies are continuing including controlling of their formation positions and chirality.
FIG. 1 shows one example of a wiring-and-via structure using such CNTs (see for example Japanese Patent Application Laid-open No. 2002-329723 (Claims) and Nihei et al, Japan Journal of Applied Physics, 2005, vol. 44, p. 1626). As shown in FIG. 1, such a via structure can be prepared for example by providing an underlayer 2 and a Cu wiring layer 3 on a substrate 1, depositing a barrier film 4 (a Ta film or the like) on the Cu wiring layer 3 to prevent Cu diffusion, forming an insulating layer 5 thereupon, forming via holes and depositing a catalytic metal support film 6 (a Ti film or the like) and a catalytic metal film 7 of Co or the like therein by a method such as sputtering, and then growing CNTs 8 by a method such as thermal CVD (chemical vapor deposition) using hydrocarbon gas (CH4, C2H2 or the like), after which the upper wiring is formed.